From the Rolls-Royce experimental archive: a quarter of a million communications from Rolls-Royce, 1906 to 1960's. Documents from the Sir Henry Royce Memorial Foundation (SHRMF).
Practice of pinning piston rings for aero and car engines and a proposal to change it.
| Identifier | ExFiles\Box 178\3\ img176 | |
| Date | 5th May 1932 | |
| F.C. HS.{Lord Ernest Hives - Chair}) FROM R.{Sir Henry Royce} C. to SG.{Arthur F. Sidgreaves - MD} WOB ORIGINAL R2/M24 5.32. X 7040. X 5040. X 3996. X4465. PISTONS - AERO, & CAR ENGINES. For over 25 yrs. we have been pinning our piston rings, but we understand from some recent memos. that you are asking for standardisation sheets for deleting pinning of the rings on aero engines. Naturally we should be slow to make such a change. I am quite willing however to agree to delete the pins in the top ring and the scraper ring, and leave the middle two (of the four) pinned as usual. We should be sure then that we have one joint sealed by the pressure of contact of the piston itself upon the cylinder wall, whichever side the angle of the con. rod thrusts the piston. I have never found the practice of pinning to have any disadvantage, if well carried out to our rules, and it is an enormous advantage to be sure that all the joints are not opposite one another, say at the side of the piston where there is no wall contact, in which unfortunate condition we may get a bad blow through, blowing the lubrication out, and perhaps seizing the piston. We assume that the suggestion of deleting the pins must be because it is hoped that the rings will keep more free. Whether the pistons are really gas-tight is especially noticeable on good slow running of car engines, and our pistons have always been noted for this property. I should have written earlier about this subject, but have been too ill for a week or two to put pen to paper. R | ||